linux-toradex.git/net/mptcp/subflow.c, branch v6.7

mptcp: prevent tcp diag from closing listener subflows

2024-01-03T00:12:47+00:00

The MPTCP protocol does not expect that any other entity could change
the first subflow status when such socket is listening.
Unfortunately the TCP diag interface allows aborting any TCP socket,
including MPTCP listeners subflows. As reported by syzbot, that trigger
a WARN() and could lead to later bigger trouble.

The MPTCP protocol needs to do some MPTCP-level cleanup actions to
properly shutdown the listener. To keep the fix simple, prevent
entirely the diag interface from stopping such listeners.

We could refine the diag callback in a later, larger patch targeting
net-next.

Fixes: 57fc0f1ceaa4 ("mptcp: ensure listener is unhashed before updating the sk status")
Cc: stable@vger.kernel.org
Reported-by: 
Closes: https://lore.kernel.org/netdev/0000000000004f4579060c68431b@google.com/
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts 
Link: https://lore.kernel.org/r/20231226-upstream-net-20231226-mptcp-prevent-warn-v1-2-1404dcc431ea@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: fix inconsistent state on fastopen race

2023-12-17T20:54:22+00:00

The netlink PM can race with fastopen self-connect attempts, shutting
down the first subflow via:

MPTCP_PM_CMD_DEL_ADDR -> mptcp_nl_remove_id_zero_address ->
  mptcp_pm_nl_rm_subflow_received -> mptcp_close_ssk

and transitioning such subflow to FIN_WAIT1 status before the syn-ack
packet is processed. The MPTCP code does not react to such state change,
leaving the connection in not-fallback status and the subflow handshake
uncompleted, triggering the following splat:

  WARNING: CPU: 0 PID: 10630 at net/mptcp/subflow.c:1405 subflow_data_ready+0x39f/0x690 net/mptcp/subflow.c:1405
  Modules linked in:
  CPU: 0 PID: 10630 Comm: kworker/u4:11 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
  Workqueue: bat_events batadv_nc_worker
  RIP: 0010:subflow_data_ready+0x39f/0x690 net/mptcp/subflow.c:1405
  Code: 18 89 ee e8 e3 d2 21 f7 40 84 ed 75 1f e8 a9 d7 21 f7 44 89 fe bf 07 00 00 00 e8 0c d3 21 f7 41 83 ff 07 74 07 e8 91 d7 21 f7 <0f> 0b e8 8a d7 21 f7 48 89 df e8 d2 b2 ff ff 31 ff 89 c5 89 c6 e8
  RSP: 0018:ffffc90000007448 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffff888031efc700 RCX: ffffffff8a65baf4
  RDX: ffff888043222140 RSI: ffffffff8a65baff RDI: 0000000000000005
  RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000007
  R10: 000000000000000b R11: 0000000000000000 R12: 1ffff92000000e89
  R13: ffff88807a534d80 R14: ffff888021c11a00 R15: 000000000000000b
  FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fa19a0ffc81 CR3: 000000007a2db000 CR4: 00000000003506f0
  DR0: 000000000000d8dd DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Call Trace:
   
   tcp_data_ready+0x14c/0x5b0 net/ipv4/tcp_input.c:5128
   tcp_data_queue+0x19c3/0x5190 net/ipv4/tcp_input.c:5208
   tcp_rcv_state_process+0x11ef/0x4e10 net/ipv4/tcp_input.c:6844
   tcp_v4_do_rcv+0x369/0xa10 net/ipv4/tcp_ipv4.c:1929
   tcp_v4_rcv+0x3888/0x3b30 net/ipv4/tcp_ipv4.c:2329
   ip_protocol_deliver_rcu+0x9f/0x480 net/ipv4/ip_input.c:205
   ip_local_deliver_finish+0x2e4/0x510 net/ipv4/ip_input.c:233
   NF_HOOK include/linux/netfilter.h:314 [inline]
   NF_HOOK include/linux/netfilter.h:308 [inline]
   ip_local_deliver+0x1b6/0x550 net/ipv4/ip_input.c:254
   dst_input include/net/dst.h:461 [inline]
   ip_rcv_finish+0x1c4/0x2e0 net/ipv4/ip_input.c:449
   NF_HOOK include/linux/netfilter.h:314 [inline]
   NF_HOOK include/linux/netfilter.h:308 [inline]
   ip_rcv+0xce/0x440 net/ipv4/ip_input.c:569
   __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5527
   __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5641
   process_backlog+0x101/0x6b0 net/core/dev.c:5969
   __napi_poll.constprop.0+0xb4/0x540 net/core/dev.c:6531
   napi_poll net/core/dev.c:6600 [inline]
   net_rx_action+0x956/0xe90 net/core/dev.c:6733
   __do_softirq+0x21a/0x968 kernel/softirq.c:553
   do_softirq kernel/softirq.c:454 [inline]
   do_softirq+0xaa/0xe0 kernel/softirq.c:441
   
   
   __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:381
   spin_unlock_bh include/linux/spinlock.h:396 [inline]
   batadv_nc_purge_paths+0x1ce/0x3c0 net/batman-adv/network-coding.c:471
   batadv_nc_worker+0x9b1/0x10e0 net/batman-adv/network-coding.c:722
   process_one_work+0x884/0x15c0 kernel/workqueue.c:2630
   process_scheduled_works kernel/workqueue.c:2703 [inline]
   worker_thread+0x8b9/0x1290 kernel/workqueue.c:2784
   kthread+0x33c/0x440 kernel/kthread.c:388
   ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
   ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
   

To address the issue, catch the racing subflow state change and
use it to cause the MPTCP fallback. Such fallback is also used to
cause the first subflow state propagation to the msk socket via
mptcp_set_connected(). After this change, the first subflow can
additionally propagate the TCP_FIN_WAIT1 state, so rename the
helper accordingly.

Finally, if the state propagation is delayed to the msk release
callback, the first subflow can change to a different state in between.
Cache the relevant target state in a new msk-level field and use
such value to update the msk state at release time.

Fixes: 1e777f39b4d7 ("mptcp: add MSG_FASTOPEN sendmsg flag support")
Cc: stable@vger.kernel.org
Reported-by: 
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/458
Signed-off-by: Paolo Abeni 
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts 
Signed-off-by: David S. Miller

Merge tag 'v6.7-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

2023-11-03T02:15:30+00:00

Pull crypto updates from Herbert Xu:
 "API:
   - Add virtual-address based lskcipher interface
   - Optimise ahash/shash performance in light of costly indirect calls
   - Remove ahash alignmask attribute

  Algorithms:
   - Improve AES/XTS performance of 6-way unrolling for ppc
   - Remove some uses of obsolete algorithms (md4, md5, sha1)
   - Add FIPS 202 SHA-3 support in pkcs1pad
   - Add fast path for single-page messages in adiantum
   - Remove zlib-deflate

  Drivers:
   - Add support for S4 in meson RNG driver
   - Add STM32MP13x support in stm32
   - Add hwrng interface support in qcom-rng
   - Add support for deflate algorithm in hisilicon/zip"

* tag 'v6.7-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (283 commits)
  crypto: adiantum - flush destination page before unmapping
  crypto: testmgr - move pkcs1pad(rsa,sha3-*) to correct place
  Documentation/module-signing.txt: bring up to date
  module: enable automatic module signing with FIPS 202 SHA-3
  crypto: asymmetric_keys - allow FIPS 202 SHA-3 signatures
  crypto: rsa-pkcs1pad - Add FIPS 202 SHA-3 support
  crypto: FIPS 202 SHA-3 register in hash info for IMA
  x509: Add OIDs for FIPS 202 SHA-3 hash and signatures
  crypto: ahash - optimize performance when wrapping shash
  crypto: ahash - check for shash type instead of not ahash type
  crypto: hash - move "ahash wrapping shash" functions to ahash.c
  crypto: talitos - stop using crypto_ahash::init
  crypto: chelsio - stop using crypto_ahash::init
  crypto: ahash - improve file comment
  crypto: ahash - remove struct ahash_request_priv
  crypto: ahash - remove crypto_ahash_alignmask
  crypto: gcm - stop using alignmask of ahash
  crypto: chacha20poly1305 - stop using alignmask of ahash
  crypto: ccm - stop using alignmask of ahash
  net: ipv6: stop checking crypto_ahash_alignmask
  ...

ipv6: drop feature RTAX_FEATURE_ALLFRAG

2023-10-26T01:04:29+00:00

RTAX_FEATURE_ALLFRAG was added before the first git commit:

https://www.mail-archive.com/bk-commits-head@vger.kernel.org/msg03399.html

The feature would send packets to the fragmentation path if a box
receives a PMTU value with less than 1280 byte. However, since commit
9d289715eb5c ("ipv6: stop sending PTB packets for MTU < 1280"), such
message would be simply discarded. The feature flag is neither supported
in iproute2 utility. In theory one can still manipulate it with direct
netlink message, but it is not ideal because it was based on obsoleted
guidance of RFC-2460 (replaced by RFC-8200).

The feature would always test false at the moment, so remove related
code or mark them as unused.

Signed-off-by: Yan Zhai 
Reviewed-by: Florian Westphal 
Reviewed-by: Eric Dumazet 
Link: https://lore.kernel.org/r/d78e44dcd9968a252143ffe78460446476a472a1.1698156966.git.yan@cloudflare.com
Signed-off-by: Jakub Kicinski

mptcp: refactor sndbuf auto-tuning

2023-10-25T19:23:35+00:00

The MPTCP protocol account for the data enqueued on all the subflows
to the main socket send buffer, while the send buffer auto-tuning
algorithm set the main socket send buffer size as the max size among
the subflows.

That causes bad performances when at least one subflow is sndbuf
limited, e.g. due to very high latency, as the MPTCP scheduler can't
even fill such buffer.

Change the send-buffer auto-tuning algorithm to compute the main socket
send buffer size as the sum of all the subflows buffer size.

Reviewed-by: Mat Martineau 
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-9-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: consolidate sockopt synchronization

2023-10-25T19:23:34+00:00

Move the socket option synchronization for active subflows
at subflow creation time. This allows removing the now unused
unlocked variant of such helper.

While at that, clean-up a bit the mptcp_subflow_create_socket()
errors path.

Reviewed-by: Mat Martineau 
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-7-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: give rcvlowat some love

2023-10-25T19:23:34+00:00

The MPTCP protocol allow setting sk_rcvlowat, but the value there
is currently ignored.

Additionally, the default subflows sk_rcvlowat basically disables per
subflow delayed ack: the MPTCP protocol move the incoming data from the
subflows into the msk socket as soon as the TCP stacks invokes the subflow
data_ready callback. Later, when __tcp_ack_snd_check() takes action,
the subflow-level copied_seq matches rcv_nxt, and that mandate for an
immediate ack.

Let the mptcp receive path be aware of such threshold, explicitly tracking
the amount of data available to be ready and checking vs sk_rcvlowat in
mptcp_poll() and before waking-up readers.

Additionally implement the set_rcvlowat() callback, to properly handle
the rcvbuf auto-tuning on sk_rcvlowat changes.

Finally to properly handle delayed ack, force the subflow level threshold
to 0 and instead explicitly ask for an immediate ack when the msk level th
is not reached.

Reviewed-by: Mat Martineau 
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-5-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: use plain bool instead of custom binary enum

2023-10-25T19:23:34+00:00

The 'data_avail' subflow field is already used as plain boolean,
drop the custom binary enum type and switch to bool.

No functional changed intended.

Reviewed-by: Mat Martineau 
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-3-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: fix delegated action races

2023-10-05T16:34:31+00:00

The delegated action infrastructure is prone to the following
race: different CPUs can try to schedule different delegated
actions on the same subflow at the same time.

Each of them will check different bits via mptcp_subflow_delegate(),
and will try to schedule the action on the related per-cpu napi
instance.

Depending on the timing, both can observe an empty delegated list
node, causing the same entry to be added simultaneously on two different
lists.

The root cause is that the delegated actions infra does not provide
a single synchronization point. Address the issue reserving an additional
bit to mark the subflow as scheduled for delegation. Acquiring such bit
guarantee the caller to own the delegated list node, and being able to
safely schedule the subflow.

Clear such bit only when the subflow scheduling is completed, ensuring
proper barrier in place.

Additionally swap the meaning of the delegated_action bitmask, to allow
the usage of the existing helper to set multiple bit at once.

Fixes: bcd97734318d ("mptcp: use delegate action to schedule 3rd ack retrans")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau 
Signed-off-by: Paolo Abeni 
Signed-off-by: Mat Martineau 
Link: https://lore.kernel.org/r/20231004-send-net-20231004-v1-1-28de4ac663ae@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: fix dangling connection hang-up

2023-09-18T11:47:56+00:00

According to RFC 8684 section 3.3:

  A connection is not closed unless [...] or an implementation-specific
  connection-level send timeout.

Currently the MPTCP protocol does not implement such timeout, and
connection timing-out at the TCP-level never move to close state.

Introduces a catch-up condition at subflow close time to move the
MPTCP socket to close, too.

That additionally allows removing similar existing inside the worker.

Finally, allow some additional timeout for plain ESTABLISHED mptcp
sockets, as the protocol allows creating new subflows even at that
point and making the connection functional again.

This issue is actually present since the beginning, but it is basically
impossible to solve without a long chain of functional pre-requisites
topped by commit bbd49d114d57 ("mptcp: consolidate transition to
TCP_CLOSE in mptcp_do_fastclose()"). When backporting this current
patch, please also backport this other commit as well.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/430
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts 
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts 
Signed-off-by: David S. Miller